[PATCH v2] powerpc/bpf: populate extable entries only during the last pass

Hari Bathini hbathini at linux.ibm.com
Tue Apr 25 16:58:29 AEST 2023

Since commit 85e031154c7c ("powerpc/bpf: Perform complete extra passes
to update addresses"), two additional passes are performed to avoid
space and CPU time wastage on powerpc. But these extra passes led to
WARN_ON_ONCE() hits in bpf_add_extable_entry() as extable entries are
populated again, during the extra pass, without resetting the index.
Fix it by resetting entry index before repopulating extable entries,
if and when there is an additional pass.

Fixes: 85e031154c7c ("powerpc/bpf: Perform complete extra passes to update addresses")
Cc: stable at vger.kernel.org
Signed-off-by: Hari Bathini <hbathini at linux.ibm.com>
 arch/powerpc/net/bpf_jit_comp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index e93aefcfb83f..37043dfc1add 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -101,6 +101,8 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
 		bpf_hdr = jit_data->header;
 		proglen = jit_data->proglen;
 		extra_pass = true;
+		/* During extra pass, ensure index is reset before repopulating extable entries */
+		cgctx.exentry_idx = 0;
 		goto skip_init_ctx;

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